Introduce dedicated NPDisk::TLogCache

17 files changed, 339 insertions, 54 deletions

diff --git a/ydb/core/blobstorage/pdisk/CMakeLists.darwin-x86_64.txt b/ydb/core/blobstorage/pdisk/CMakeLists.darwin-x86_64.txt
index 378ee761763..69594119e22 100644
--- a/ydb/core/blobstorage/pdisk/CMakeLists.darwin-x86_64.txt
+++ b/ydb/core/blobstorage/pdisk/CMakeLists.darwin-x86_64.txt
@@ -56,6 +56,7 @@ target_sources(core-blobstorage-pdisk PRIVATE
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl_http.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl_log.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_internal_interface.cpp
+  ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_logreader.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_mon.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_params.cpp
diff --git a/ydb/core/blobstorage/pdisk/CMakeLists.linux-aarch64.txt b/ydb/core/blobstorage/pdisk/CMakeLists.linux-aarch64.txt
index 1fd378a19b2..14483b3155f 100644
--- a/ydb/core/blobstorage/pdisk/CMakeLists.linux-aarch64.txt
+++ b/ydb/core/blobstorage/pdisk/CMakeLists.linux-aarch64.txt
@@ -57,6 +57,7 @@ target_sources(core-blobstorage-pdisk PRIVATE
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl_http.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl_log.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_internal_interface.cpp
+  ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_logreader.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_mon.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_params.cpp
diff --git a/ydb/core/blobstorage/pdisk/CMakeLists.linux-x86_64.txt b/ydb/core/blobstorage/pdisk/CMakeLists.linux-x86_64.txt
index 1fd378a19b2..14483b3155f 100644
--- a/ydb/core/blobstorage/pdisk/CMakeLists.linux-x86_64.txt
+++ b/ydb/core/blobstorage/pdisk/CMakeLists.linux-x86_64.txt
@@ -57,6 +57,7 @@ target_sources(core-blobstorage-pdisk PRIVATE
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl_http.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl_log.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_internal_interface.cpp
+  ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_logreader.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_mon.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_params.cpp
diff --git a/ydb/core/blobstorage/pdisk/CMakeLists.windows-x86_64.txt b/ydb/core/blobstorage/pdisk/CMakeLists.windows-x86_64.txt
index 378ee761763..69594119e22 100644
--- a/ydb/core/blobstorage/pdisk/CMakeLists.windows-x86_64.txt
+++ b/ydb/core/blobstorage/pdisk/CMakeLists.windows-x86_64.txt
@@ -56,6 +56,7 @@ target_sources(core-blobstorage-pdisk PRIVATE
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl_http.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl_log.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_internal_interface.cpp
+  ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_logreader.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_mon.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_params.cpp
diff --git a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_blockdevice.h b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_blockdevice.h
index 7469ec76d8a..1388ec92fa4 100644
--- a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_blockdevice.h
+++ b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_blockdevice.h
@@ -47,6 +47,7 @@ public:
     virtual void CachedPreadAsync(void *data, ui32 size, ui64 offset, TCompletionAction *completionAction,
             TReqId reqId, NWilson::TTraceId *traceId) = 0;
     virtual void ClearCache() = 0;
+    virtual void EraseCacheRange(ui64 begin, ui64 end) = 0; // erases offsets range [begin, end)
     virtual void FlushAsync(TCompletionAction *completionAction, TReqId reqId) = 0;
     virtual void NoopAsync(TCompletionAction *completionAction, TReqId reqId) = 0;
     virtual void NoopAsyncHackForLogReader(TCompletionAction *completionAction, TReqId reqId) = 0;
@@ -61,11 +62,13 @@ public:
     virtual TString DebugInfo() = 0;
 };
 
+class TPDisk;
+
 IBlockDevice* CreateRealBlockDevice(const TString &path, ui32 pDiskId, TPDiskMon &mon,
         ui64 reorderingCycles, ui64 seekCostNs, ui64 deviceInFlight, TDeviceMode::TFlags flags,
-        ui32 maxQueuedCompletionActions, TIntrusivePtr<TSectorMap> sectorMap);
+        ui32 maxQueuedCompletionActions, TIntrusivePtr<TSectorMap> sectorMap, TPDisk * const pdisk = nullptr);
 IBlockDevice* CreateRealBlockDeviceWithDefaults(const TString &path, TPDiskMon &mon, TDeviceMode::TFlags flags,
-        TIntrusivePtr<TSectorMap> sectorMap, TActorSystem *actorSystem);
+        TIntrusivePtr<TSectorMap> sectorMap, TActorSystem *actorSystem, TPDisk * const pdisk = nullptr);
 
 } // NPDisk
 } // NKikimr
diff --git a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_blockdevice_async.cpp b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_blockdevice_async.cpp
index a66a3f911e1..6a53d162b12 100644
--- a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_blockdevice_async.cpp
+++ b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_blockdevice_async.cpp
@@ -1,6 +1,8 @@
 #include "blobstorage_pdisk_blockdevice.h"
 #include <ydb/library/pdisk_io/buffers.h>
 #include "blobstorage_pdisk_completion_impl.h"
+#include "blobstorage_pdisk_impl.h"
+#include "blobstorage_pdisk_log_cache.h"
 #include "blobstorage_pdisk_mon.h"
 #include "blobstorage_pdisk_util_atomicblockcounter.h"
 #include "blobstorage_pdisk_util_countedqueuemanyone.h"
@@ -11,7 +13,6 @@
 #include <ydb/core/base/appdata.h>
 #include <ydb/core/blobstorage/lwtrace_probes/blobstorage_probes.h>
 #include <ydb/core/protos/services.pb.h>
-#include <ydb/core/util/cache.h>
 #include <ydb/core/util/yverify_stream.h>
 #include <ydb/library/pdisk_io/aio.h>
 #include <ydb/library/pdisk_io/spdk_state.h>
@@ -1198,48 +1199,29 @@ class TCachedBlockDevice : public TRealBlockDevice {
         }
     };
 
-    struct TCacheRecord : public TThrRefBase {
-        char *Data;
-        ui64 Size;
-        TVector<ui64> BadOffsets;
-
-        TCacheRecord(TCachedReadCompletion *source)
-            : Data(static_cast<char*>(malloc(source->GetSize())))
-            , Size(source->GetSize())
-            , BadOffsets(std::move(source->GetBadOffsets()))
-        {
-            memcpy(Data, source->GetData(), source->GetSize());
-        }
-
-        ~TCacheRecord() {
-            free(Data);
-        }
-    };
-
     static constexpr ui64 MaxCount = 500ull;
     static constexpr ui64 MaxReadsInFly = 2;
 
     TMutex CacheMutex;
-    NCache::TLruCache<ui64, TIntrusivePtr<TCacheRecord>> Cache;
+    TLogCache Cache; // cache records MUST NOT cross chunk boundaries
     TMultiMap<ui64, TRead> ReadsForOffset;
     TMap<ui64, TCachedReadCompletion*> CurrentReads;
     ui64 ReadsInFly;
+    TPDisk * const PDisk;
 
     void UpdateReads() {
         auto nextIt = ReadsForOffset.begin();
         for (auto it = ReadsForOffset.begin(); it != ReadsForOffset.end(); it = nextIt) {
             nextIt++;
             TRead &read = it->second;
-            TIntrusivePtr<TCacheRecord> *found;
-            bool isFound = Cache.Find(read.Offset, found);
-            if (isFound) {
-                TCacheRecord &cached = *found->Get();
-                if (read.Size <= cached.Size) {
-                    memcpy(read.Data, cached.Data, read.Size);
+            const TLogCache::TCacheRecord* cached = Cache.Find(read.Offset);
+            if (cached) {
+                if (read.Size <= cached->Data.Size()) {
+                    memcpy(read.Data, cached->Data.GetData(), read.Size);
                     Mon.DeviceReadCacheHits->Inc();
                     Y_VERIFY(read.CompletionAction);
-                    for (size_t i = 0; i < cached.BadOffsets.size(); ++i) {
-                        read.CompletionAction->RegisterBadOffset(cached.BadOffsets[i]);
+                    for (size_t i = 0; i < cached->BadOffsets.size(); ++i) {
+                        read.CompletionAction->RegisterBadOffset(cached->BadOffsets[i]);
                     }
                     NoopAsyncHackForLogReader(read.CompletionAction, read.ReqId);
                     ReadsForOffset.erase(it);
@@ -1270,13 +1252,14 @@ class TCachedBlockDevice : public TRealBlockDevice {
 public:
     TCachedBlockDevice(const TString &path, ui32 pDiskId, TPDiskMon &mon, ui64 reorderingCycles,
             ui64 seekCostNs, ui64 deviceInFlight, TDeviceMode::TFlags flags, ui32 maxQueuedCompletionActions,
-            TIntrusivePtr<TSectorMap> sectorMap)
+            TIntrusivePtr<TSectorMap> sectorMap, TPDisk * const pdisk)
         : TRealBlockDevice(path, pDiskId, mon, reorderingCycles, seekCostNs, deviceInFlight, flags,
                 maxQueuedCompletionActions, sectorMap)
-        , ReadsInFly(0)
+        , ReadsInFly(0), PDisk(pdisk)
     {}
 
     void ExecRead(TCachedReadCompletion *completion, TActorSystem *actorSystem) {
+        Y_ASSERT(PDisk);
         TStackVec<TCompletionAction*, 32> pendingActions;
         {
             TGuard<TMutex> guard(CacheMutex);
@@ -1284,28 +1267,42 @@ public:
             auto currentReadIt = CurrentReads.find(offset);
             Y_VERIFY(currentReadIt != CurrentReads.end());
             auto range = ReadsForOffset.equal_range(offset);
-            if (Cache.GetCount() >= MaxCount) {
-                Cache.Pop();
+
+            ui64 chunkIdx = offset / PDisk->Format.ChunkSize;
+            Y_VERIFY(chunkIdx < PDisk->ChunkState.size());
+            if (TChunkState::DATA_COMMITTED == PDisk->ChunkState[chunkIdx].CommitState) {
+                if ((offset % PDisk->Format.ChunkSize) + completion->GetSize() > PDisk->Format.ChunkSize) {
+                    // TODO: split buffer if crossing chunk boundary instead of completely discarding it
+                    LOG_INFO_S(
+                        *ActorSystem, NKikimrServices::BS_DEVICE,
+                        "Skip caching log read due to chunk boundary crossing");
+                } else {
+                    if (Cache.Size() >= MaxCount) {
+                        Cache.Pop();
+                    }
+                    const char* dataPtr = static_cast<const char*>(completion->GetData());
+                    Cache.Insert(
+                        TLogCache::TCacheRecord(
+                            completion->GetOffset(),
+                            TRcBuf(TString(dataPtr, dataPtr + completion->GetSize())),
+                            completion->GetBadOffsets()));
+                }
             }
-            TIntrusivePtr<TCacheRecord> cacheRecord(new TCacheRecord(completion));
-            TIntrusivePtr<TCacheRecord> *junk;
-            Cache.Erase(offset);
-            bool isOk = Cache.Insert(offset, cacheRecord, junk);
-            Y_VERIFY(isOk);
+
             auto nextIt = range.first;
             for (auto it = range.first; it != range.second; it = nextIt) {
                 nextIt++;
                 TRead &read = it->second;
                 if (read.Size <= completion->GetSize()) {
                     if (read.Data != completion->GetData()) {
-                        memcpy(read.Data, cacheRecord->Data, read.Size);
+                        memcpy(read.Data, completion->GetData(), read.Size);
                         Mon.DeviceReadCacheHits->Inc();
                     } else {
                         Mon.DeviceReadCacheMisses->Inc();
                     }
                     Y_VERIFY(read.CompletionAction);
-                    for (size_t i = 0; i < cacheRecord->BadOffsets.size(); ++i) {
-                        read.CompletionAction->RegisterBadOffset(cacheRecord->BadOffsets[i]);
+                    for (ui64 badOffset : completion->GetBadOffsets()) {
+                        read.CompletionAction->RegisterBadOffset(badOffset);
                     }
                     pendingActions.push_back(read.CompletionAction);
                     ReadsForOffset.erase(it);
@@ -1360,6 +1357,11 @@ public:
         Cache.Clear();
     }
 
+    virtual void EraseCacheRange(ui64 begin, ui64 end) override {
+        TGuard<TMutex> guard(CacheMutex);
+        Cache.EraseRange(begin, end);
+    }
+
     void Stop() override {
         TRealBlockDevice::Stop();
         for (auto it = CurrentReads.begin(); it != CurrentReads.end(); ++it) {
@@ -1377,14 +1379,14 @@ public:
 
 IBlockDevice* CreateRealBlockDevice(const TString &path, ui32 pDiskId, TPDiskMon &mon, ui64 reorderingCycles,
         ui64 seekCostNs, ui64 deviceInFlight, TDeviceMode::TFlags flags, ui32 maxQueuedCompletionActions,
-        TIntrusivePtr<TSectorMap> sectorMap) {
+        TIntrusivePtr<TSectorMap> sectorMap, TPDisk * const pdisk) {
     return new TCachedBlockDevice(path, pDiskId, mon, reorderingCycles, seekCostNs, deviceInFlight, flags,
-            maxQueuedCompletionActions, sectorMap);
+            maxQueuedCompletionActions, sectorMap, pdisk);
 }
 
 IBlockDevice* CreateRealBlockDeviceWithDefaults(const TString &path, TPDiskMon &mon, TDeviceMode::TFlags flags,
-        TIntrusivePtr<TSectorMap> sectorMap, TActorSystem *actorSystem) {
-    IBlockDevice *device = CreateRealBlockDevice(path, 0, mon, 0, 0, 4, flags, 8, sectorMap);
+        TIntrusivePtr<TSectorMap> sectorMap, TActorSystem *actorSystem, TPDisk * const pdisk) {
+    IBlockDevice *device = CreateRealBlockDevice(path, 0, mon, 0, 0, 4, flags, 8, sectorMap, pdisk);
     device->Initialize(actorSystem, {});
     return device;
 }
diff --git a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_driveestimator.cpp b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_driveestimator.cpp
index d4e7f0e2231..2ea7e9e61cc 100644
--- a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_driveestimator.cpp
+++ b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_driveestimator.cpp
@@ -236,7 +236,7 @@ TDriveEstimator::TDriveEstimator(const TString filename)
     , ActorSystemCreator(new TActorSystemCreator)
     , ActorSystem(ActorSystemCreator->GetActorSystem())
     , QueueDepth(4)
-    , Device(CreateRealBlockDevice(filename, 0, PDiskMon, 50, 0, QueueDepth, TDeviceMode::LockFile, 128, nullptr))
+    , Device(CreateRealBlockDevice(filename, 0, PDiskMon, 50, 0, QueueDepth, TDeviceMode::LockFile, 128, nullptr, nullptr))
     , BufferPool(CreateBufferPool(BufferSize, 1, false, {}))
     , Buffer(BufferPool->Pop())
 {
diff --git a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl.cpp b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl.cpp
index 748c7105280..5c3027d21ac 100644
--- a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl.cpp
+++ b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl.cpp
@@ -45,7 +45,7 @@ TPDisk::TPDisk(const TIntrusivePtr<TPDiskConfig> cfg, const TIntrusivePtr<::NMon
     , BlockDevice(CreateRealBlockDevice(cfg->GetDevicePath(), cfg->PDiskId, Mon,
                     HPCyclesMs(ReorderingMs), DriveModel.SeekTimeNs(), cfg->DeviceInFlight,
                     TDeviceMode::LockFile | (cfg->UseSpdkNvmeDriver ? TDeviceMode::UseSpdk : 0),
-                    cfg->MaxQueuedCompletionActions, cfg->SectorMap))
+                    cfg->MaxQueuedCompletionActions, cfg->SectorMap, this))
     , Cfg(cfg)
     , CreationTime(TInstant::Now())
     , ExpectedSlotCount(cfg->ExpectedSlotCount)
diff --git a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl_log.cpp b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl_log.cpp
index 392776190c6..74951e1676d 100644
--- a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl_log.cpp
+++ b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl_log.cpp
@@ -1137,6 +1137,12 @@ void TPDisk::OnLogCommitDone(TLogCommitDone &req) {
 void TPDisk::MarkChunksAsReleased(TReleaseChunks& req) {
     TGuard<TMutex> guard(StateMutex);
 
+    for (const auto& chunkIdx : req.ChunksToRelease) {
+        BlockDevice->EraseCacheRange(
+            Format.Offset(chunkIdx, 0), 
+            Format.Offset(chunkIdx + 1, 0));
+    }
+
     if (req.IsChunksFromLogSplice) {
         auto *releaseReq = ReqCreator.CreateFromArgs<TReleaseChunks>(std::move(req.ChunksToRelease));
 
diff --git a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache.cpp b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache.cpp
new file mode 100644
index 00000000000..7d225c2efa9
--- /dev/null
+++ b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache.cpp
@@ -0,0 +1,82 @@
+#include "blobstorage_pdisk_log_cache.h"
+
+namespace NKikimr {
+namespace NPDisk {
+
+TLogCache::TCacheRecord::TCacheRecord(ui64 offset, TRcBuf data, TVector<ui64> badOffsets)
+    : Offset(offset)
+    , Data(std::move(data))
+    , BadOffsets(std::move(badOffsets))
+{}
+
+TLogCache::TCacheRecord::TCacheRecord(TCacheRecord&& other)
+    : Offset(other.Offset)
+    , Data(std::move(other.Data))
+    , BadOffsets(std::move(other.BadOffsets))
+{}
+
+TLogCache::TItem::TItem(TItem&& other) 
+    : Value(std::move(other.Value))
+{}
+
+TLogCache::TItem::TItem(TCacheRecord&& value)
+    : Value(std::move(value))
+{}
+
+size_t TLogCache::Size() const {
+    return Index.size();
+}
+
+const TLogCache::TCacheRecord* TLogCache::Find(ui64 offset) {
+    auto indexIt = Index.find(offset);
+    if (indexIt == Index.end()) {
+        return nullptr;
+    }
+
+    List.PushFront(&indexIt->second);
+    return &indexIt->second.Value;
+}
+
+const TLogCache::TCacheRecord* TLogCache::FindWithoutPromote(ui64 offset) const {
+    auto indexIt = Index.find(offset);
+    if (indexIt == Index.end()) {
+        return nullptr;
+    }
+    
+    return &indexIt->second.Value;
+}
+
+bool TLogCache::Pop() {
+    if (Index.empty())
+        return false;
+
+    TItem* item = List.PopBack();
+    Index.erase(item->Value.Offset);
+    return true;
+}
+
+bool TLogCache::Insert(TCacheRecord&& value) {
+    auto [it, inserted] = Index.try_emplace(value.Offset, std::move(value));
+    List.PushFront(&it->second); 
+    return inserted;
+}
+
+size_t TLogCache::Erase(ui64 offset) {
+    return Index.erase(offset);
+}
+
+size_t TLogCache::EraseRange(ui64 begin, ui64 end) {
+    Y_VERIFY_DEBUG(begin <= end);
+    auto beginIt = Index.lower_bound(begin);
+    auto endIt = Index.lower_bound(end);
+    size_t dist = std::distance(beginIt, endIt);
+    Index.erase(beginIt, endIt);
+    return dist;
+}
+
+void TLogCache::Clear() {
+    Index.clear();
+}
+
+} // NPDisk
+} // NKikimr
diff --git a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache.h b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache.h
new file mode 100644
index 00000000000..c3d91dcdd2c
--- /dev/null
+++ b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache.h
@@ -0,0 +1,54 @@
+#pragma once
+#include "defs.h"
+#include <library/cpp/actors/util/rc_buf.h>
+#include <util/generic/intrlist.h>
+#include <util/generic/hash.h>
+
+namespace NKikimr {
+namespace NPDisk {
+
+/**
+ * Key-value LRU cache without automatic eviction, but able to erase range of keys.
+ **/
+class TLogCache {
+public:
+    struct TCacheRecord {
+        ui64 Offset = 0;
+        TRcBuf Data;
+        TVector<ui64> BadOffsets;
+
+        TCacheRecord() = default;
+        TCacheRecord(TCacheRecord&&);
+        TCacheRecord(ui64 offset, TRcBuf data, TVector<ui64> badOffsets);
+    };
+
+private:
+    struct TItem : public TIntrusiveListItem<TItem> {
+        TCacheRecord Value;
+
+        // custom constructors ignoring TIntrusiveListItem
+        TItem(TItem&& other);
+        explicit TItem(TCacheRecord&& value);
+    };
+
+    using TListType = TIntrusiveList<TItem>;
+    using TIndex = TMap<ui64, TItem>;
+
+public:
+    size_t Size() const;
+    const TCacheRecord* Find(ui64 offset);
+    const TCacheRecord* FindWithoutPromote(ui64 offset) const;
+
+    bool Pop();
+    bool Insert(TCacheRecord&& value);
+    size_t Erase(ui64 offset);
+    size_t EraseRange(ui64 begin, ui64 end);  // erases range [begin, end)
+    void Clear();
+
+private:
+    TListType List;
+    TIndex Index;
+};
+
+} // NPDisk
+} // NKikimr
diff --git a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache_ut.cpp b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache_ut.cpp
new file mode 100644
index 00000000000..ba0d99e641a
--- /dev/null
+++ b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache_ut.cpp
@@ -0,0 +1,126 @@
+#include "blobstorage_pdisk_log_cache.h"
+
+#include <library/cpp/testing/unittest/registar.h>
+
+namespace NKikimr {
+namespace NPDisk {
+
+Y_UNIT_TEST_SUITE(TLogCache) {
+    TLogCache::TCacheRecord MakeRecord(ui64 offset, TString str) {
+        return TLogCache::TCacheRecord(
+            offset,
+            TRcBuf(TString(str.c_str(), str.c_str() + str.size() + 1)),
+            {});
+    }
+
+    Y_UNIT_TEST(Simple) {
+        TLogCache cache;
+
+        UNIT_ASSERT(cache.Insert(MakeRecord(1, "a")));
+        UNIT_ASSERT(cache.Insert(MakeRecord(2, "b")));
+        UNIT_ASSERT_EQUAL(cache.Size(), 2);
+        UNIT_ASSERT_STRINGS_EQUAL(cache.Find(1)->Data.GetData(), "a");
+
+        UNIT_ASSERT(cache.Insert(MakeRecord(3, "c")));
+        UNIT_ASSERT(cache.Pop()); // 2 must be evicted
+        UNIT_ASSERT_EQUAL(cache.Size(), 2);
+        UNIT_ASSERT_EQUAL(nullptr, cache.Find(2));
+        UNIT_ASSERT_STRINGS_EQUAL(cache.Find(3)->Data.GetData(), "c");
+
+        UNIT_ASSERT(cache.Pop()); // 1 must be evicted
+        UNIT_ASSERT(cache.Insert(MakeRecord(4, "d")));
+
+        UNIT_ASSERT_EQUAL(cache.Size(), 2);
+        UNIT_ASSERT_EQUAL(nullptr, cache.Find(1));
+        UNIT_ASSERT_STRINGS_EQUAL(cache.Find(4)->Data.GetData(), "d");
+
+        UNIT_ASSERT(cache.Pop()); // 3 must be evicted
+        UNIT_ASSERT_EQUAL(cache.Size(), 1);
+        UNIT_ASSERT_EQUAL(nullptr, cache.Find(3));
+        UNIT_ASSERT_STRINGS_EQUAL(cache.Find(4)->Data.GetData(), "d");
+
+        UNIT_ASSERT_EQUAL(0, cache.Erase(3));
+        UNIT_ASSERT_EQUAL(1, cache.Erase(4));
+        UNIT_ASSERT_EQUAL(cache.Size(), 0);
+        UNIT_ASSERT(!cache.Pop());
+        UNIT_ASSERT_EQUAL(cache.Size(), 0);
+    }
+
+    TLogCache SetupCache(const TVector<std::pair<ui64, TString>>& content = {{5, "x"}, {1, "y"}, {10, "z"}}) {
+        TLogCache cache;
+        for (auto pair : content) {
+            cache.Insert(MakeRecord(pair.first, pair.second));
+        }
+        return cache;
+    };
+
+    void AssertCacheContains(TLogCache& cache, const TVector<std::pair<ui64, TString>>& content = {{5, "x"}, {1, "y"}, {10, "z"}}) {
+        UNIT_ASSERT_VALUES_EQUAL(content.size(), cache.Size());
+        for (auto pair : content) {
+            UNIT_ASSERT_STRINGS_EQUAL(
+                pair.second,
+                cache.FindWithoutPromote(pair.first)->Data.GetData());
+        }
+        for (auto pair : content) {
+            UNIT_ASSERT(cache.Pop());
+            UNIT_ASSERT_EQUAL(nullptr, cache.FindWithoutPromote(pair.first));
+        }
+    }
+
+    Y_UNIT_TEST(EraseRangeOnEmpty) {
+        TLogCache cache;
+        UNIT_ASSERT_EQUAL(0, cache.EraseRange(0, 0));
+        UNIT_ASSERT_EQUAL(0, cache.EraseRange(0, 10));
+        UNIT_ASSERT_EQUAL(0, cache.EraseRange(10, 10));
+    }
+
+    Y_UNIT_TEST(EraseRangeOutsideOfData) {
+        TLogCache cache = SetupCache();
+        UNIT_ASSERT_EQUAL(3, cache.Size());
+        UNIT_ASSERT_EQUAL(0, cache.EraseRange(0, 1));
+        UNIT_ASSERT_EQUAL(3, cache.Size());
+        UNIT_ASSERT_EQUAL(0, cache.EraseRange(11, 12));
+        UNIT_ASSERT_EQUAL(3, cache.Size());
+        UNIT_ASSERT_EQUAL(0, cache.EraseRange(11, 100));
+        UNIT_ASSERT_EQUAL(3, cache.Size());
+    }
+
+    Y_UNIT_TEST(EraseRangeSingleMinElement) {
+        TLogCache cache = SetupCache();
+        UNIT_ASSERT_EQUAL(1, cache.EraseRange(1, 2));
+        AssertCacheContains(cache, {{5, "x"}, {10, "z"}});
+    }
+
+    Y_UNIT_TEST(EraseRangeSingleMidElement) {
+        TLogCache cache = SetupCache();
+        UNIT_ASSERT_EQUAL(1, cache.EraseRange(5, 6));
+        AssertCacheContains(cache, {{1, "y"}, {10, "z"}});
+    }
+
+    Y_UNIT_TEST(EraseRangeSingleMaxElement) {
+        TLogCache cache = SetupCache();
+        UNIT_ASSERT_EQUAL(1, cache.EraseRange(10, 11));
+        AssertCacheContains(cache, {{5, "x"}, {1, "y"}});
+    }
+
+    Y_UNIT_TEST(EraseRangeSample) {
+        TLogCache cache = SetupCache();
+        UNIT_ASSERT_EQUAL(2, cache.EraseRange(2, 100));
+        AssertCacheContains(cache, {{1, "y"}});
+    }
+
+    Y_UNIT_TEST(EraseRangeAllExact) {
+        TLogCache cache = SetupCache();
+        UNIT_ASSERT_EQUAL(3, cache.EraseRange(1, 11));
+        UNIT_ASSERT_EQUAL(0, cache.Size());
+    }
+
+    Y_UNIT_TEST(EraseRangeAllAmple) {
+        TLogCache cache = SetupCache();
+        UNIT_ASSERT_EQUAL(3, cache.EraseRange(0, 100));
+        UNIT_ASSERT_EQUAL(0, cache.Size());
+    }
+}
+
+} // NPDisk
+} // NKikimr
diff --git a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_logreader.cpp b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_logreader.cpp
index 532ad750833..add4a820ac2 100644
--- a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_logreader.cpp
+++ b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_logreader.cpp
@@ -793,11 +793,11 @@ bool TLogReader::ProcessSectorSet(TSectorData *sector) {
                     << " LastGoodToWriteLogPosition# " << LastGoodToWriteLogPosition
                     << " Marker# LR018");
         } else {
-//           Y_VERIFY_S(ChunkIdx == LogEndChunkIdx && SectorIdx >= LogEndSectorIdx, SelfInfo()
-//                   << " File# " << __FILE__
-//                   << " Line# " << __LINE__
-//                   << " LogEndChunkIdx# " << LogEndChunkIdx
-//                   << " LogEndSectorIdx# " << LogEndSectorIdx);
+           Y_VERIFY_S(ChunkIdx == LogEndChunkIdx && SectorIdx >= LogEndSectorIdx, SelfInfo()
+                   << " File# " << __FILE__
+                   << " Line# " << __LINE__
+                   << " LogEndChunkIdx# " << LogEndChunkIdx
+                   << " LogEndSectorIdx# " << LogEndSectorIdx);
             if (!(ChunkIdx == LogEndChunkIdx && SectorIdx >= LogEndSectorIdx)) {
                 LOG_WARN_S(*PDisk->ActorSystem, NKikimrServices::BS_PDISK, SelfInfo()
                         << " In ProcessSectorSet got !restorator.GoodSectorFlags outside the LogEndSector."
@@ -1147,6 +1147,11 @@ void TLogReader::Reply() {
     if (IsInitial) {
         PDisk->ProcessChunkOwnerMap(*ChunkOwnerMap.Get());
         ChunkOwnerMap.Destroy();
+
+        PDisk->BlockDevice->EraseCacheRange(
+            PDisk->Format.Offset(ChunkIdx, 0),
+            PDisk->Format.Offset(ChunkIdx + 1, 0)
+        );
     }
     LOG_DEBUG(*PDisk->ActorSystem, NKikimrServices::BS_PDISK, "PDiskId# %" PRIu32 " To ownerId# %" PRIu32 " %s",
         (ui32)PDisk->PDiskId, (ui32)Owner, Result->ToString().c_str());
@@ -1387,4 +1392,3 @@ void TLogReader::ReleaseUsedBadOffsets() {
 
 } // NPDisk
 } // NKikimr
-
diff --git a/ydb/core/blobstorage/pdisk/ut/CMakeLists.darwin-x86_64.txt b/ydb/core/blobstorage/pdisk/ut/CMakeLists.darwin-x86_64.txt
index 5472736fd16..95f69321e94 100644
--- a/ydb/core/blobstorage/pdisk/ut/CMakeLists.darwin-x86_64.txt
+++ b/ydb/core/blobstorage/pdisk/ut/CMakeLists.darwin-x86_64.txt
@@ -32,6 +32,7 @@ target_link_options(ydb-core-blobstorage-pdisk-ut PRIVATE
 target_sources(ydb-core-blobstorage-pdisk-ut PRIVATE
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_blockdevice_ut.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_crypto_ut.cpp
+  ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache_ut.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_util_ut.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_ut_env.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_ut_races.cpp
diff --git a/ydb/core/blobstorage/pdisk/ut/CMakeLists.linux-aarch64.txt b/ydb/core/blobstorage/pdisk/ut/CMakeLists.linux-aarch64.txt
index eb05ab2715d..faef05f81f8 100644
--- a/ydb/core/blobstorage/pdisk/ut/CMakeLists.linux-aarch64.txt
+++ b/ydb/core/blobstorage/pdisk/ut/CMakeLists.linux-aarch64.txt
@@ -35,6 +35,7 @@ target_link_options(ydb-core-blobstorage-pdisk-ut PRIVATE
 target_sources(ydb-core-blobstorage-pdisk-ut PRIVATE
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_blockdevice_ut.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_crypto_ut.cpp
+  ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache_ut.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_util_ut.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_ut_env.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_ut_races.cpp
diff --git a/ydb/core/blobstorage/pdisk/ut/CMakeLists.linux-x86_64.txt b/ydb/core/blobstorage/pdisk/ut/CMakeLists.linux-x86_64.txt
index 8ad3a8a33fb..268016dec16 100644
--- a/ydb/core/blobstorage/pdisk/ut/CMakeLists.linux-x86_64.txt
+++ b/ydb/core/blobstorage/pdisk/ut/CMakeLists.linux-x86_64.txt
@@ -36,6 +36,7 @@ target_link_options(ydb-core-blobstorage-pdisk-ut PRIVATE
 target_sources(ydb-core-blobstorage-pdisk-ut PRIVATE
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_blockdevice_ut.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_crypto_ut.cpp
+  ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache_ut.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_util_ut.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_ut_env.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_ut_races.cpp
diff --git a/ydb/core/blobstorage/pdisk/ut/CMakeLists.windows-x86_64.txt b/ydb/core/blobstorage/pdisk/ut/CMakeLists.windows-x86_64.txt
index 83968ce047d..0533f6adb7d 100644
--- a/ydb/core/blobstorage/pdisk/ut/CMakeLists.windows-x86_64.txt
+++ b/ydb/core/blobstorage/pdisk/ut/CMakeLists.windows-x86_64.txt
@@ -25,6 +25,7 @@ target_link_libraries(ydb-core-blobstorage-pdisk-ut PUBLIC
 target_sources(ydb-core-blobstorage-pdisk-ut PRIVATE
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_blockdevice_ut.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_crypto_ut.cpp
+  ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_log_cache_ut.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_util_ut.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_ut_env.cpp
   ${CMAKE_SOURCE_DIR}/ydb/core/blobstorage/pdisk/blobstorage_pdisk_ut_races.cpp